.tu p{
    background-color: white;
    width: 70px;
    height: 70px;
    float: left;
    margin-right: 2px;
    margin-top: 2px;
    border-radius: 3px;
    transform: translateY(-1000px);
    animation:ai 0.6s infinite;
    opacity: 0;
    
}
@keyframes ai{
    20%,70%{
        transform: translateY(0px);opacity: 1;
    }
    100%{
        transform: translateY(0px)
    }
}
.tu{
    width:100%;
    height: 100px;
    padding-top: 150px;
    color:snow;
    margin: auto;
}
.tu .yx{
    background: none;
}
.tu .yc1{animation-delay: 0.1s;}
.tu .yc2{animation-delay: 0.2s;}
.tu .yc3{animation-delay: 0.3s;}
.tu .yc4{animation-delay: 0.4s;}
.tu .yc5{animation-delay: 0.5s;}